Experimental analysis of aluminum yield surface for binary AlMg alloy sheet samples

Abstract In this work, the yield surfaces of binary aluminum-magnesium alloy sheet samples were measured using biaxial compression tests. Sheet samples of a given material were stacked and bonded together with epoxy and cubic compression specimens were machined out of the laminate. The yielding behavior was assumed to be independent of the hydrostatic pressure. In the analysis of the biaxial compression tests, the effects of friction and of the elasticity of the die were accounted for. These effects were studied with the aid of finite element method (FEM) simulations of the test which proved to be useful in avoiding systematic errors. The yield surfaces of three binary alloy sheet samples containing 5 wt% Mg but with different crystallographic textures were analyzed. The different textures resulted from processing under different thermomechanical conditions. The experimental yield surfaces were compared to predictions made with the Taylor-Bishop and Hill (TBH) model and with a phenomenological yield function. The experimental and polycrystal yield surfaces were found to be in fair agreement. The yield function was found to be a suitable description of the plastic behavio for only two of the materials studied.